The present disclosure relates to Positron Emission Tomography (PET) data acquisition, more particularly to accessing information associated with detector detectors installed in a PET scanner.
Nuclear medicine is a unique medical specialty wherein radiation is used to acquire images which show the function and anatomy of organs, bones or tissues of the body. Radiopharmaceuticals are introduced into the body, either by injection or ingestion, and are attracted to specific organs, bones or tissues of interest. Such radiopharmaceuticals produce gamma photon emissions which emanate from the body and are captured by a scintillation crystal, with which the photons interact to produce flashes of light or “events.” Events are detected by an array of photodetectors, such as photomultiplier tubes, and their spatial locations or positions are calculated and stored. In this way, an image of the organ or tissue under study is created from detection of the distribution of the radioisotopes in the body.
One particular nuclear medicine imaging technique is known as Positron Emission Tomography, or PET. PET is used to produce images for diagnosing the biochemistry or physiology of a specific organ, tumor or other metabolically active site. Measurement of the tissue concentration of a positron emitting radionuclide is based on coincidence detection of the two gamma photons arising from positron annihilation. When a positron is annihilated by an electron, two 511 keV gamma photons are simultaneously produced and travel in approximately opposite directions. Gamma photons produced by an annihilation event can be detected by a pair of oppositely disposed radiation detectors capable of producing a signal in response to the interaction of the gamma photons with a scintillation crystal. Annihilation events are typically identified by a time coincidence between the detection of the two 511 keV gamma photons in the two oppositely disposed detectors, i.e., the gamma photon emissions are detected virtually simultaneously by each detector. When two oppositely disposed gamma photons each strike an oppositely disposed detector to produce a time coincidence event, they also identify a line of response, or LOR, along which the annihilation event has occurred.
Radiation detectors typically are deployed in an array of axially aligned rings, each ring comprising a plurality of individual detectors. For example, scanner detector modules may contain three or four rings of forty eight detectors in each ring. PET scanner manufacturers are mandated by regulatory agencies to maintain a device history record for each scanner, which include, for example, part numbers and serial numbers of all traceable components, including detectors. The specific installation location, ring and angular position, are also to be kept in the record.
The device history record normally is maintained by hand inspection or by use of bar code readers. Application of such process for tracking the large number of individual detectors is time consuming and prone to human errors. For example, if the detector manufacturer discovers a problem with a specific batch of detectors at any time, the locations of the problem detectors in a particular scanner, as well as all other scanners at dispersed geographical sites, must be identified. If a detector problem is found during the testing process upon installation in a particular scanner, this abnormality should be recorded. Should a particular system determine that a detector is experiencing performance problems, the particular details of the problem, and conditions under which it was observed, should be included in a history record for review when field service personnel retrieves the affected detector and returns it to the manufacturer for post-failure analysis.
Detector identification is also needed for scanners that may need to permit or restrict certain functionality based on the model number and/or serial number of the detectors installed in the scanners. For example, a system containing lower-grade detectors might be restricted to certain lower-grade image processing algorithms or algorithms that were tailored to a specific model of detector.
The need thus exists for an easier and more efficient way to track important information associated with individual PET scan detectors and to readily obtain such information at a later date.